/*
{
    const a=10;
    a=20;
    console.log(a);
}*/

/*
{
    let a=10;
    a=20;
    console.log(a);
}*/
/*
{
    //let a;
    const a=1;
    console.log(a);
}*/
{
    const obj={
        user:'张三'
    }
    obj.user='李四';
    obj.pwd='123456';
    console.log(obj.user,obj.pwd);
}